Ellis, a 53-year-old army veteran who lives in the neighborhood and once worked for the Red Cross, did everything he could to save the life of the officer.

"Another guy from across the street helped me roll him over, took his helmet off and his glasses and we tried to stop the bleeding from his neck," Ellis said.

He used his coat to try to stop the bleeding, but it was too late.

In all four officers died at the hands of Lovelle Mixon following a routine traffic stop and a shootout at a nearby apartment. Mixon was a parolee with a warrant out for his arrest. Police investigators told the San Francisco Chronicle Mixon was suspected in up to five rape cases in the neighborhood where the shootings took place; one of the victims was a 12-year-old girl.

Acting Oakland Police Chief Howard Jordan said the department will reward Ellis, but nothing can ever repay him for what he did that day.

"He really was one of the heroes on Saturday, in the face of what had just transpired," Jordan said.

"Ever since I've seen it, it's something that's clearly embedded in my immediate thoughts," Ellis said. "He had a pulse, I kept a pulse on him, he had a pulse the entire time. Then it got faint, for a while, then I guess, the rest was just over," Ellis said.